To the Editor.—At least five published studies which Weibel et al did not cite have indicated that joint reactions to rubella vaccination do occur in children under 12 years of age. Although these were all retrospective studies, there is little doubt that these reactions do occur in young school children. Frequency and severity are greater for dog kidney vaccines as opposed to other types, yet 4% to 5% incidence in school children who received duck embryo vaccine has been demonstrated. Although these joint reactions are usually mild, a virtual absence of these complications should not be expected.

To the Editor.—Drs. Kolansky and Moore (222:35, 1972) are to be commended for their careful clinical studies of the toxic effects of long-term cannabis use. One would hope that this type of clinical assessment of adverse effects would receive at least as much public attention as uninformed laymen's enthusiastic endorsements.The